420 HEALTH AND DISEASE 



which the wire is pressed after it has been threaded (fig. 421), or the end 

 of the wire is in other examples passed into a hole at the end of the 

 needle (fig. 422). 



Difficulty is sometimes experienced in forcing needles through the skin 

 or other hard tissues. This is overcome by the employment of suture 

 forceps (fig. 423), which allows of additional pressure being exercised upon 

 the needle, and guards against that tendency to slip which occurs when the 

 fingers alone are employed. 



" Carbolic Acid, the first antiseptic introduced by Lister, has a direct 

 germicidal action in strong solutions and an inhibitory effect in weaker 

 ones. The crystals when heated with 10 per cent of water constitute an 

 oily fluid known as pure or liquefied carbolic acid, which is a powerful 

 though superficial caustic, and may be employed without much fear to 

 infected lesions, in order, if possible, to sterilize them. Thus it is always 

 well to treat tuberculous wounds with this fluid after scraping them, in 

 order to destroy any portions of tuberculous material which may have 

 escaped the spoon. The liquid carbolic dissolves in water on the applica- 

 tion of a little warmth, and the l-in-20 and l-in-40 solutions are those 

 mainly employed ; the former is an efficient and potent antiseptic, and must 

 be used carefully on delicate skins. Carbolic acid is frequently somewhat 

 crude and impure, and many of the irritative and toxic phenomena are due 

 to cresylic acid and other substances which should not be present. General 

 absorption of this reagent leads to darkening of the urine, which may 

 become olive-green or even black in colour, and this carboluria is often 

 associated with a rise in temperature and some intestinal irritation, whilst 

 diseased kidneys may be seriously affected. It is more likely to occur 

 when weaker solutions are employed than when the liquefied or pure acid 

 is applied. The latter is seldom absorbed." 



" Corrosive Sublimate is a valuable though very poisonous remedy 

 which is usually employed in solutions of 1 in 2000, 1 in 1000, or 1 in 500. 

 Occasionally the last of these three solutions has 5 per cent of carbolic acid 

 added to it, constituting what is known as Lister's strong mixture. Subli- 

 mate solutions are inhibitory in action rather than germicidal, but are 

 potent and reliable. They have less power of penetration than carbolic 

 acid, but have no hardening or roughening influence on the skin. If, how- 

 ever, a dressing soaked in a sublimate solution (1 in 2000) is kept for long 

 in contact with the skin, it acts as a direct irritant, and may lead to an 



